How to do pivot from table-type variable
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Hi,
I have this table-type data
tdata.yearID=[1950;1950;1950;1951;1951;1951;1951;1952;1952;1952];
tdata.cluster=[1;3;4;1;2;3;4;1;2;3];
tdata.GroupCount=[5;2;6;2;2;4;2;1;2;2];
tdata= struct2table( tdata)
tdata =
10×3 table
yearID cluster GroupCount
______ _______ __________
1950 1 5
1950 3 2
1950 4 6
1951 1 2
1951 2 2
1951 3 4
1951 4 2
1952 1 1
1952 2 2
1952 3 2
Currently I am using this code below to do pivot, but it was very slow for large data. Is there a way to vectorize this code?
[uniqYr, ~, JYr]= unique( tdata.yearID);
nEventData.yearID= [1: 2000]';
[ nEventData.cnt]= zeros( length(nEventData.yearID), 4);
for runYr= 1: length( uniqYr)
indxYr= uniqYr( runYr);
tloc = (JYr== runYr);
tt = tdata( tloc, :);
nEventData.cnt( indxYr, tt.cluster')= tt.GroupCount';
end % for runYr
So results look like this for rows 1949-1955. Other rows have zeros.
nEventData.cnt (1949:1955,:)
ans =
0 0 0 0
5 0 2 6
2 2 4 2
1 2 2 0
0 0 0 0
0 0 0 0
0 0 0 0
2 个评论
Peter Perkins
2018-10-5
Pete, your code does not run and it's not at all clear what you want as your result. You are going to need to be much more clear.
Peter Perkins
2018-10-5
The updated question and output clarify that unstack does what you need, as Steve suggests.
采纳的回答
Steven Lord
2018-10-5
The output you described looks somewhat like the first example in the documentation for the unstack function. I think what you want is something close to the pivotedTdata variable created by this example:
tdata.yearID=[1950;1950;1950;1951;1951;1951;1951;1952;1952;1952];
tdata.cluster=[1;3;4;1;2;3;4;1;2;3];
tdata.GroupCount=[5;2;6;2;2;4;2;1;2;2];
tdata= struct2table( tdata)
pivotedTdata = unstack(tdata, 'GroupCount', 'cluster')
You can retrieve data for a particular year this way:
pivotedTdata(pivotedTdata.yearID == 1950, :)
更多回答（1 个）
Lola Davidson
2023-3-17
3 个投票
pivotedTable = pivot(tdata, Rows="yearID", Columns="cluster", DataVariable="GroupCount");
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